Method of hardening and tempering metal



Patented Oct. 4, 1932 UNITE SATES PATENT FF'ECE JESSE LANDON, OF LIMA, OHIO, ASSIGNOR OF ONE-SIXTH TO WILLIAM L CBUM-RINE, OF

LIMA,

METHOD OF HARDENING No Drawing. Application filed April 7,

metal is rendered extremely hard and at the same time is given a temper which will avoid that brittleness which would be expected to attend the degree of hardness communicated.

The invention has for another object to provide an improved method for treating metal, such as iron and steel, by which desirable properties of temper and hardness are imparted to the metal in such relative degrees as to provide a substantially new metallic product suitable for use in building structures, either fixed, such as houses, office buildings and the like or movable, such as automobiles and aeroplane frames, wherein because of the hardness and strength of the metal, a less amount of such metal may be employed with the same degree of security and strength, thereby reducing the cost of such building.

The new metallic product or material 1 formed is also applicable to all of the uses in the arts to which a metal having these properties is put; for instance razor blades may be made from the improved metal and due to the hardness and temper thereof will a preserve their cutting edges for a longer space of time than is now deemed possible with present metals.

The invention also aims to secure the above advantages by the use of a method, the steps of which are few and simple, and which will not require the use of special apparatus or any extraordinary skill in the factory operatives performing the same.

In carrying out the improved method, the following five steps are employed preferably in the order named:

First: Initially linseed oil is heated to a. boiling point.

Second: As the oil approaches its boiling point, and just before it arrives at such boiling point, resin is added to the oil in the proportion of one-eighth of a pound of the resin to each gallon of linseed oil. The action is allowed to go on until the resin is all taken up by the oil.

OHIO

AND 'rEMri'iRn IG' METAL 1932. Serial No. 6033901.

Third: The iron, steei or other metal to be treated is then placed in the boiling solu tion of oil and resin and allowed to remain therein until such metal has acquired the same temperature throughout its mass as the boiling solution of oil and resin.

Fourth: Having reached this temperature,- the metal is removed from the solution and immediately covered over -With powdered resin, which will be absorbed by" the metal. 50 While this absorption will be substantially instantaneous, the action will preferably be allowed to go on for some few minutes before.

Fifth: The metal is plunged into cold coal-- oil, wherein it is permitted to remain until 06' the temperature of the' metal is substantially equalized with that of the coal-oil.

The metal is thenremoved and will be found to have new qualities of hardness and temper which will haveconverted such metal into a substantially new product possessing great tensile and compressive strength, high ductility, as well as apeculiarly high degree of hardness and an accompanying high temper.

Any linseed oil maybe employed in the first step, either raw or r'efined,but the raw oil is cheaper and will admirably accom-V plish the result. Such linseed oil acts to initially soften the iron or the steel. The linseed oil must be'br'ought to the boiling point in order to act upon the metal to bring such metal to the same temperature. At such temperature the softening action above referred to of the oil on the metal iswhat is required for the most successful carrying out of the later steps of the method. Moreover, such high temperature ofthe oil is shown to be the proper stage for adding the'resin. If a lower temperature of the oil obtains, the resin will not be properly absorbed if a highertemperature is used, the resin gums rather than becomes uniformly diffused ,and absorbed throughout the solution. The fisin is thus thoroughly melted and distributed throughout the linseed oil and a mechanical mixture is formed.

The proportions of the oil and resin are probably critical, although I wish a certain latitude in these proportions, but tests using exactly one-eighth of a pound of resin to one gallon of oil showed the best results. With less resin there was a too thin mixture. Where more resin was used, the oil became thick and the resin was not fully absorbed.

The boiling oil and resin solution acts to soften the ,metal as above stated and permit more complete absorption of the solution, which is necessary in order that the hardening process that follows may be satisfac tory.

The metal throughout this mass must be brought to the temperature of the boiling oil and resin, because there is less absorption at either lower or higher temperatures. The metal rapidly reaches the required temperature due to its high conductivity.

When covered with the powdered resin, the iron .or steel will absorb a superficial amount of the same, partially hardening the metal. The coal-oil has the effect of driving this powdered resin into the iron or steel. Coal-oil'is preferred over water or some other cold bath as it has been found to act I in a more efficacious manner in driving the resin into the pores of the heated metal.

1 The iron or steel is left in the coal-oil bath until the temperature equalizes because it is demonstrated that it is necessary to have a slow, ratherthan a rapid, process. If the iron or steel is 'taken out before the equalization,it toughens rather than hardens; if it remains until equalization, it hardens and tempers the iron or steel.

I desire it to be understood that various changes and modifications may be made in the steps of the method and in temperature ranges without departing from the spirit of the invention provided such changes are within the scope of the following claim:

What is claimed is:

The herein-described method for tempering and hardening metal, which consists in heating linseed oil substantially to its boiling point, adding resin in substantially the proportionof one-eighth of a pound of resin to each gallon of oil, immersing the metal in the solution of resin and oil until the metal acquires the temperature of the solution, subsequentlyremoving the metal and covering the same with powdered resin, andplunging the metal into cold coal-oil, permitting the metal to remain in the bath until the temperature of the metal is equalized with that of the '1 coal-oil.

In testimony whereof I afiix my signature.

JESSE LANDON. 

